BROWNE— MEDUSA FROM THE INDIAN OCEAN 189 



to modern requirements. At present, 1 have no valid reasons for ranking ^quorea 

 parva as a synonym. 



It appears to me, in spite of the descriptions and figures given by Maas and myself 

 of Mesonema pensile and /Equorea macrodactyla, that Vanhoffen has failed to see clearly 

 the difference between the two species. In his sketch (1911, p. 223, text-fig. 21) of the 

 margin of umbrella showing the basal portion of the tentacles of Mesonema pensile, they 

 appear to be very much like the basal bulbs of y^quorea macrodactyla ; they are not at 

 all like the basal bulbs of a genuine Mesonema pensile. 



In the "Sealark" collection there is only one specimen, which is in very bad 

 condition. By the shape of the basal bulbs I think it is Mesonema pensile. The 

 umbrella is about 15 mm. in diameter. There are eight tentacles. The radial canal 

 system is practically destroyed, just a few canals left. 



Distribution. Tropical Pacific and Indian Oceans. Maas (1909) records it from 

 Sagami Bay (35° N., 139° 37' E.), Japan. 



24. ^QUOREA MACRODACTYLA (Brandt) 1834. 



JSquorea maldivensis, Browne, 1904, p. 732, pi. 56, figs. 4 — 12. 

 Mesonema macrodactylum, Maas, 1905, p. 40, Taf. 8, figs. 51 and 54. 

 ^Equorea macrodactyla, Bigelovv, 1909, p. 37, pi. 36, figs. 5 — 10. 



Localities. North of Chagos. 1200 — fms. 17 May, 1905, 0. 1 specimen. 

 Chagos Archipelago, Salomon Atoll. 180 — fms. 30 June, 1905, O. 1 specimen. 

 Saga de Malha. 55 — fms. 6 Sept. 1905, C. 14. 8 specimens. 



jEquorea macrodactyla of Brandt received a description according to modern 

 requirements by Maas in 1905, and more recently Bigelow has published an account 

 of some specimens taken in the Eastern Tropical Pacific. As the two best specimens 

 in the "Sealark" collection agree very well with the descriptions given by Maas and 

 Bigelow, I have no doubt that we have all seen the same species. 



In one of my earlier publications on Medusae I pointed out that the shape of the 

 basal bulbs of the tentacles was a useful aid in the determination of the species belonging 

 to the iEquoridee. There are distinct types of basal bulbs, and for each type an allowance ' 

 must be made for variation and also for contraction or distortion due to preservation. 

 yEquorea inacrodactyla has the basal bulbs curling over or clasping a thickening of the 

 margin of the umbrella, and the character is clearly seen when a tentacle is cut out from 

 the umbrella and viewed sideways. 



Maas, when he re-described jEquorea rtiacrodactyla, pointed out that its basal bulbs 

 belonged to the same type as that found in ^i^quorea m,aldivensis, which had then not 

 long been described by me as a new species. Bigelow, however, has gone a step 

 further and considers JEquorea maldivensis to be the same species as JEquorea m,acro- 

 dactyla. It would now be very hard for me to keep the two species apart except by 

 hair-splitting differences which, as far as possible, should be avoided. 



The basal bulbs of the " Sealark" specimens are more like those figured by Maas and 

 Bigelow for jEquorea macrodactyla than those figured by me for j^quorea maldivensis, 

 but the type is the same and the differences would come within the range of variation, 



